1. Field of the Invention
This invention relates to a structure for a seat for an automotive vehicle and more particularly to a device for adjusting the height of a cushion member of such a seat.
2. Description of the Prior Art
In a conventional automobile seat structure 10, as shown in FIG. 1, a cushion member 31 is supported by a first supporting member 18, a second supporting member 19, a third supporting member 21 and a fourth supporting member 28. The four supporting members 18, 19, 21 and 28 are formed as bell cranks and are so mechanically coupled together that they may be moved simultaneously for adjusting the height of the cushion member 31 upon pivoting of the first supporting member 18.
In order to rotate the first supporting member 18, a handle-operated coupler 40 is conventionally employed. The coupler 40 has a rotating member 60 including a pinion 61 which is in mesh with a geared portion 62 of the first supporting member 18.
However, backlash may be generated between the pinion 61 and the geared portion 62. With a view to avoiding such backlash, extremely high accuracy or precision is required for manufacturing the pinion 61 and the geared portion 62 with attendant high costs.